﻿/**
* Formats the number according to the 'format' string;
* adherses to the american number standard where a comma
* is inserted after every 3 digits.
*  note: there should be only 1 contiguous number in the format,
* where a number consists of digits, period, and commas
*        any other characters can be wrapped around this number, including '$', '%', or text
*        examples (123456.789):
*          '0′ - (123456) show only digits, no precision
*          '0.00′ - (123456.78) show only digits, 2 precision
*          '0.0000′ - (123456.7890) show only digits, 4 precision
*          '0,000′ - (123,456) show comma and digits, no precision
*          '0,000.00′ - (123,456.78) show comma and digits, 2 precision
*          '0,0.00′ - (123,456.78) shortcut method, show comma and digits, 2 precision
*
* @method format
* @param format {string} the way you would like to format this text
* @return {string} the formatted number
* @public
*/ 

Number.prototype.format = function(format) {
  if (! isType(format, 'string')) {return '';} // sanity check 

  var hasComma = -1 < format.indexOf(','),
    psplit = format.stripNonNumeric().split('.'),
    that = this; 

  // compute precision
  if (1 < psplit.length) {
    // fix number precision
    that = that.toFixed(psplit[1].length);
  }
  // error: too many periods
  else if (2 < psplit.length) {
    throw('NumberFormatException: invalid format, formats should have no more than 1 period: ' + format);
  }
  // remove precision
  else {
    that = that.toFixed(0);
  } 

  // get the string now that precision is correct
  var fnum = that.toString(); 

  // format has comma, then compute commas
  if (hasComma) {
    // remove precision for computation
    psplit = fnum.split('.'); 

    var cnum = psplit[0],
      parr = [],
      j = cnum.length,
      m = Math.floor(j / 3),
      n = cnum.length % 3 || 3; // n cannot be ZERO or causes infinite loop 

    // break the number into chunks of 3 digits; first chunk may be less than 3
    for (var i = 0; i < j; i += n) {
      if (i != 0) {n = 3;}
      parr[parr.length] = cnum.substr(i, n);
      m -= 1;
    } 

    // put chunks back together, separated by comma
    fnum = parr.join(','); 

    // add the precision back in
    if (psplit[1]) {fnum += '.' + psplit[1];}
  } 

  // replace the number portion of the format with fnum
  return format.replace(/[\d,?\.?]+/, fnum);
};